In the lamp base designation "E-10" (sometimes called Miniature Edison
Screw (MES), "E" stands for "Edison" and "10" indicates the diameter in
millimeters as measured across the peaks of the thread on the base, e.g.,
E-10 base bulbs have a diameter of 10 mm. E-10 base light bulbs have a
single contact on the bottom and are used in flashlights, indicators and toys. Other International
designations for the E-10 base is IEC (International Electrotechnical
Commission) # 7004-22 and DIN (German Institute for Standardization) #
49610.